The present invention relates to a method of forming a slot of varying cross-section in a workpiece.
The invention also relates to apparatus for achieving the aforementioned aperture.
Previous attempts to provide a machine tool with which to produce a slot or recess in a workpiece, which slot or recess has a varying cross-section, are typified in published specifications GB2061141 and GB2092048. The arrangement disclosed in the former specification suffered wear through friction. The arrangement disclosed in the later specification is controlled by a numerical control system and numerous motors and is consequently expensive.
The example in GB2061141 is effectively a self contained machine tool in that it is movement of the electrode vertically downwards, which brings about varying reciprocatory movement of the workpiece laterally thereof, by varying the angle of a swashplate with respect to a pin which engages it and is caused to orbit by a motor.